John Cuthber

I'm not a geochemist, but doesn't "volcanic ash" cover a huge range of possible materials?

Did you look at the picture? It is a cage- albeit one with rather sparse bars. It is also a conductor.

Keep the current low and the concentration low is the summary of all the advice I have heard about this but I think it's an art as much as a science. Be prepared to get it wrong lots of times before you get it right.

FeCO3 is green. It oxidises very quickly in air to a godforsaken mixture of Fe(II) and Fe(III) carbonates/ oxides. I think that you are getting some mixed oxidation state oxide but I doubt it's close to the stoichiometry for magnetite.

And for killing bacteria etc.

I used an old one as a low pressure air receiver.

Klaynos, I wonder if we are talking at crossed purposes here. This sort of thing. http://en.wikipedia.org/wiki/Pylon looks to me like it would act as a Farady cage for anyone inside it. It's conductive and it's earthed. Cages don't need solid sides (Or Mr Faraday's "box" would be beter known). Why don't you think it's a Faraday cage?

It may be an unutterably dumb idea, as well as illegal, but I think climbing the tower itself isn't a shock hazard. There's enough distance from the conductors to the tower to make sure ther's no arcover even in high winds and heavy rain. On a calm, dry day it should be safe. particularly if you climb up the inside of the tower. Of course, if you try this and get hurt don't blame me. I already said it was dumb.

I told you it needed a really dark filter.

You could use some wax or varnish rather than the oxide. Coat the work with varnish or wax, scribe through the wax, plate it with silver (the wax will stop the plating so only the bits where there's no wax will get plated. Then warm it to melt the wax off or take the varnish off with paint stripper. Part of the problem will be that it's very difficult to get a decent coating with silver- it tends to give a black mess rather than nice shiny silver.

The particular series I gave gets very dull . Other sequences may be more interesting but I suspect that for most practical ones you end up with the nth derivative being zero (for high enough n). If the motion of the object can be described by an nth order polynomial then the nth derivative is pretty dull. A whole ot of functions can be aproximated reasonably well by polynomials so I think it's fair to assume that these things generally get dull for large n. If anyone can do the maths for an object sliding down a cateneray curve it might be more interesting.

I doubt that any drink bottle is strong enough to stand the sort of pressure that would supress freezing to any noticable extent. I think it's much more likely that what Pleiades observed was supercooling.

Imagine a weight tied on a string moving with constant speed in a circle. The acceleration is a vector pointing from the weight to the middle of the circle. The first derivative of that is a vector moving in a circle in the same direction as the weight. The second derivative is a vector pointing to the centre of the circle and the thrid derivative is a vector moving in a circle in the same direction as the weight. As n tends to infinity this sequence gets infinitely boring.

"The answer, I think is 'no' because, as far as I'm aware, super cooled liquids can only occur when you only have a few molecules, unless your adding external pressure. " Well, I have seen a test tube full and there's no theoretical limit to how much you can have. I think it's plausible enough for the plot of a murder mystery but probably not reliable enough to try it.

Hypercube, are you ignoring my question because you can't answer it, or are you just being rude?

There are other complications. The molecules in air are traveling at about the speed of sound (on average). Once the projectile is traveling near the speed of sound very few of the air molecules "pushing" it can catch up with it.. Since they don't reach it they can't push - the force drops and so does the acceleration. That puts a limit on the top speed. hot light gases work better but there's still a limit.

There's something equally amiss with things if there are 2 objects separated by less than zero distance. Technically, I think the latest theories say Newtonian gravity may break down at really small distances, (Planck length anyone?) but it still works fine for things as big as atoms.

Hypercube, perhaps you would care to enlighten me about hydrinos. The first thing I'd like to know is whether or not there is any scientific (ie repeated by an unbiassed 3rd party) evidence for their existence. If so please let me know what. I know that there are some theories- string theory is one, where the "experimental" evidence is a bit thin. It tends to involve things like "it's internally consistent, requires no singularities and doesn't predict a half life for the proton of less than 10^30 years" But, on the other hand, lets be fair- the strings are pretty small and hard to observe. I have never actually seen an atom, but I know that, as a model, they explain things I can see. The same goes for the theoretical physicists strings. At least they provide a model that explains real observations. What do hydrinos explain?

I don't think that's what he meant. I think he meant sampling their hands after 5 min or 1 hr after washing.

"Maybe I'm being naive, but I for one believe them until it is proven otherwise." Feel free to send them your money. I don't plan to.

Can you post them to YT2095?

The IR polariseres I have seen were on a silicon substrate and, therfore, completely opaque to visible radiation. One might expect this to be what limits their usefulness in the current discussion; then you find out the price and find that that would also be a major factor. You can get proper filters at a perfectly reasonable price or you can take a risk with your eyesight.

If metal on metal friction wasn't significant car engines wouldn't need oil. Just because you don't like reality doesn't mean reality is wrong.

Crossed polarisers don't block IR very reliably. You can fry your eyes perfectly well with IR. This sort of thing http://cgi.ebay.co.uk/Telescope-Solar-Sun-Filter-425P1-fits-Meade-ETX-90_W0QQitemZ250253918145QQihZ015QQcategoryZ74923QQrdZ1QQssPageNameZWD2VQQcmdZViewItemQQ_trksidZp1638Q2em122 is quite common on ebay. Has anyone seen any spare pairs of eyes for sale?

Did nobody warn our American cousins that the price of gasoline was going to rise as it becomes rare (or at least the easy stuff to get at becomes rare?). If they had received such a warning I'm sure they would have invested in smaller cars etc.